[Grml] Problems booting GRML via fromhd

[Michael Prokop]

* Philipp Richter <philipp.richter at linbit.com> [20070821 17:36]:

> We use GRML as rescue system on our machines. The /boot partition (which sits 
> on a software raid1) of the main system includes the GRML-Kernel, initrd and 
> squashfs so in case someone unintentionally removes libc6 or does some other 
> bad things it's possible to recover the machine via the grml boot option in 
> grub.

> the good thing is that this works if the /boot partition is on ide devices 
> because the ide drivers are compiled into the kernel and the raid code in the 
> kernel autostarts the raid.

> the bad thing: it doesn't work with our new dell boxes with mpt fusion 
> controllers. the second problem here is that these boxes don't have ps/2 
> keyboard connectors and grml doesn't recognise the usb keyboard when it puts 
> me into the rescue shell ... argh.

Ok.

> here is what i did to fix these problems:

> - when grml loads the usb kernel modules it also tries to insmod usbhid.ko but 
> this one has unknown symbols because ff-memless.ko has to be loaded first. so 
> i copied ff-memless.ko to the initrd and added it to the list of usb.modules. 
> cool. now i have a keyboard.

Great, thanks for information.

> - the next thing was that the sysfs-scsi-detection code did not find my fusion 
> mpt controller. after reading /modules/scsi/scsi-modules.txt i knew why: 
> because it was missing from there. after adding the entries for it i ended 
> with a correctly detected controller but without a raid. how is the 
> scsi-modules.txt file created? by hand? maybe it would be better to generate 
> it from /lib/modules/$(uname -r)/modules.{dep,pcimap} because in these files 
> the mpt drivers where referenced ...

Thanks for information.

We use http://grml.org/files/devel/create-scsi-mod-file.sh for
generating the scsi-modules.txt file.

> - ok so after having the devices i needed to start the raid1 to access the 
> filesystem. unfortunately there is no mdadm in the initrd image of grml so i 
> had to compile a static version of mdadm and put it in /static. after this i 
> added some code to assemble all arrays in case there exists a boot option 
> fromhd=/dev/md*

Thanks again for the hint.

> ok so now everything works. great!

Excellent. Thanks a lot for sharing your patches! I'll take a closer
look at them. Regarding the mdadm stuff I hope to be able to use
live-initramfs in the near future which should give us more options
for mdadm/lvm/... out-of-the-box in the initrd/initramfs part of
booting.

> btw: grml is a really cool tool

Thanks :)

regards,
-mika-
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